1. Field of the Invention
The present invention relates to a method for feeding cut-sheet-shaped recording materials carried in parallel, and further relates to an image recording apparatus applying this feeding method.
2. Description of the Related Art
For example, in a photographic printer, an image is recorded by so-called scanning exposure. In this photographic printer, while a photosensitive material of a cut-sheet shape is nipped and fed in a sub-scanning direction by using a plurality of feed-rollers, recording light is scanned in a scanning direction perpendicular to the sub-scanning direction. In order to improve processing ability (number) of unit time, it is performed by preference that the photosensitive materials having an identical size or different sizes are arranged in the scanning direction and are simultaneously exposed (see Japanese Patent Laid-Open Publication No. 08-314022).
It is necessary for obtaining a high-quality photo print that the photosensitive material is accurately fed at the time of scanning exposure. When an anterior end of the photosensitive material butts against a feed-roller pair and a posterior end thereof leaves from the feed-roller pair, load fluctuation is caused by a shock at that time. Due to this, scanning unevenness occurs so that the quality of the photo print remarkably deteriorates. In view of this, such as described in Japanese Patent Laid-Open Publication No. 11-046262, when the anterior end of the photosensitive material reaches the feed-roller pair disposed at a downstream side of an exposure position, a nip state of this feed-roller pair is released. The photosensitive material is nipped after the anterior end thereof has passed the rollers of the feed-roller pair. And then, before the posterior end of the photosensitive material leaves from another feed-roller pair, which is disposed at an upstream side of the exposure position, the nip of this feed-roller pair is released. Mean while, in a case the photosensitive materials fed in parallel are simultaneously exposed, the feed-roller pairs are disposed in parallel, such as described in Japanese Patent Laid-Open Publication No. 2003-241321. These feed-roller pairs are individually changed between the nip state and the release state in accordance with sizes and so forth of the photosensitive materials of the respective rows. Thus, it is possible to prevent the scanning unevenness from occurring even when the photosensitive materials fed in parallel are simultaneously exposed.
By disposing the feed-roller pairs in parallel so as to correspond to the respective rows of the photosensitive materials such as described in the above Publication No. 2003-241321, the scanning unevenness of the entire rows seems to be prevented from occurring. However, since the feed-roller pairs are independently changed between the nip state and the release state, a mechanism thereof becomes complicated. Moreover, when sizes (length in the feed direction) of the photosensitive materials arranged in the scanning direction are different and when positions of the anterior ends are staggered, it is necessary to change nip timing and release timing relative to the photosensitive materials of the adjacent rows. Thus, control becomes complicated. Further, when the nip timing and the release timing of the adjacent feed-roller pairs are different, load fluctuation is caused. As a result, scanning unevenness occurs relative to the adjacent rows. In addition, when the photosensitive material has a wide width so as to overlap with the plural feed-roller pairs, load fluctuation is caused in case the nip timing and the release timing are not properly set relative to the adjacent feed-roller pairs. In this case, the scanning unevenness is likely to occur.